Transmission cooler on truck

[scott_l]

How does a transmission cooler on a truck work? I am assuming the transmission fluid circulates through a cooler kind of like a traditional radiator. But my question is………..does the fluid get “cooled” only when the truck is moving (air getting forced through the cooler) or is there fan on the cooler and the fluid should be getting cooled all the time?

What is a ball park temperature range that the fluid should be when the truck is at “normal” operating temperature (2007 chevy 1500)?

I am also guessing the cooler should keep the transmission fluid at the same temperature when I am pulling a two place trailer compared to normal every day driving.

 

[cuzzinolaf]

I have always seen transmission coolers mounted in front of the radiator and assume they work the same way you described. I don't know what temp you should run but doubt you "need" a tranny cooler for a two place. Sure, it won't hurt anything....

 

[xcr440]

If you are towing heavy loads for long periods of time, they are a good idea. My '95 3/4 ton Suburban has one factory installed. And just like your motor, there is an optimal operating temperature, but you need a guage to know what you are running at to determine if you really need one.

There is a "thermostat" bypass valve available to ensure that temperature is reached, and kept there as well, as a tranny cooler could keep the temp below what it should operate at.

 

[snow_monkey]

High temps will kill a trans. The cooler uses the air flow to cool the fluid plus the extra capacity of fluid helps dissipate the heat. There are lines that run through the radiator. In the summer air conditioning can shoot up temps and towing.

 

[michaeladams]

i thought all vehiclles had a tranny cooler.everytime i take out a radiator i have to disconect tranny lines.

 

[scott_l]

I have always seen transmission coolers mounted in front of the radiator and assume they work the same way you described. I don't know what temp you should run but doubt you "need" a tranny cooler for a two place. Sure, it won't hurt anything....

My truck came with a factory tranny cooler......I just had the fluid and filter changed (they said every thing looked good). And for some reason I have started watching the temperature (also a factory temperature gauge). It seems like most of the time my temperature is around 110-120 F. But I noticed that if I drive my truck for work to home (about 15 miles) and then let the truck sit in my drive way (still running) for a few minutes the tranny temp will increase. Hence the reason Im asking if you need air flow for the cooler to work or if there is supposed to be a fan.

 

[snocrazy]

I would say the ideal operating temp would go hand in hand with the engine coolant temp. That being why the trans cooler is built in to the engine radiator.

More load on the auto trans (towing) will create more heat. If you are towing a 2 place in winter, I would not bother adding a separate cooler.

Adding the separate trans cooler in front of the radiator is most likely going to bring down your trans operating temp. So if you have the time and money, you aren't hurting any thing. When ordering new trucks you can get a towing package that has this separate cooler from the factory.

 

[xcr440]

My 1995 Suburban will not shift into OD until the transmission reaches the correct operating temperature. I honestly don't know what that temp is, but in the winter, it takes a good 3-4 miles of driving before the transmission will shift into OD.

So too cool of an operating temp is not a good thing.

 

[cdsprague]

My truck a 2010 chevy 1500 tranny runs about 130-135 in the summer. I have seen it at 165 towing. It runs a lot cooler in the winter. I had a 2500 diesel a couple years back and winter driving would have a hard time getting to 100. The trucks had factory tranny coolers.

 

[doomsman]

A good friend with a transmission shop says you can't
run a transmission to cool within reason. the fluid has to flow.
He has a sign Kool is cool.
I pulled a large trailer grass dragging and added 2 medium
sized coolers horizontal at the bottom inside the radiator.
You can feel air moving even at an idle.
Pipe it so the fluid flows through it before entering the radiator
so as not to heat the engine coolant.

 

[lvr1000]

My 1995 Suburban will not shift into OD until the transmission reaches the correct operating temperature. I honestly don't know what that temp is, but in the winter, it takes a good 3-4 miles of driving before the transmission will shift into OD.

So too cool of an operating temp is not a good thing.

That is why when I put in aftermarket I run it through the cooler then back in to the radiator transmission line. My vehicle now has:

HD multiple-cooling systems-inc:
engine coolant, engine oil, transmission
oil, transfer case oil, pwr steering
fluid.

 

[stealthv]

My truck came with a factory tranny cooler......I just had the fluid and filter changed (they said every thing looked good). And for some reason I have started watching the temperature (also a factory temperature gauge). It seems like most of the time my temperature is around 110-120 F. But I noticed that if I drive my truck for work to home (about 15 miles) and then let the truck sit in my drive way (still running) for a few minutes the tranny temp will increase. Hence the reason Im asking if you need air flow for the cooler to work or if there is supposed to be a fan.

Your temperature is completely normal. Yes, airflow is required for maximum cooling either by the electric fan turning on or naturally at highway speeds. Look behind your grille and you'll see a small separate radiator for your transmission mounted in front of the big engine radiator.

When you drive home from work and park the truck, the transmission is still warm from driving 15 miles and doesn't instantly cool. Couple of factors playing into that -- The airfow across the transmission cooler fins has stopped and the big radatior fans don't kick on until the engine coolant is 221*F which won't happen unless you let the truck idle in the summer time for a really long period.

My 2008 runs in the 110* range driving to work and 130-140* pulling the 3-place snowmobile trailer.

 

[smokin440]

"Normal" is a hard word to describe when it comes to temps of a trans. A few different factors help with that,
1. Is it a factory installed(within the radiator)
2. is it a factory installed aux cooler(outside of radiator)
3. Aftermarket installed(outside of radiator)
4. Aftermarket installed(in series with OEM cooler)

Typically, if it is #1. It "should" be around the same temp or a little cooler then the vehicle, ~200* or so. Any of the others are a toss up really.
I know I have seen them run as cool as 110* with #3 and 4. And as warm as 225* while towing.

I have a 28,000 GVWR rated #4 installed on my 97 Silverado and I see temps around 130* w/o a load, and 165* with a load, depending on whats tagging behind. And I always tow in 3rd, never OD.

If you have access to a infrared temp gun, tag the bottom of the pan after you have been driving for a while and see what it is. Not gonna be exact but youll get a close idea. I have a gauge installed with the sender in the pan side to get a more accurate temp reading.

Obviously the #1 killer of a transmission aside from poor maintenance is heat.

xcr440- Its not that it isnt shifting into OD. Its programmed settings not allowing to converter to lock up while in OD, thus creating more heat and waiting for all other parameters(ECT, o2 readings, speed and many others) to get where they need to be before it does. So its actually in a sense the vehicles way of heating up faster. Amazing what computers can do huh?

OP- The cooler works like a radiator, air to air cooling. The temp wont necessarily be as cool as "normal everyday driving" because it has a load on it that is not usually there in the above stated. It only gets cooled when the truck is moving yes, but as the fan is running while the vehicle is idle, it does cool it a bit that way too while parked. The fluid is always being cooled as long as it is running, just not as much as if you were driving. Heat is always being created though.
Dont always trust your factory gauge, use a temp gun or get an aux gauge if you are really cautious. There is a port on the left (driver) side of the 4L60E just above the range selector unit that you can put the sensor in if youd rather not drill a hole and weld a plate in on the pan. Wont be as accurate, but it will be fairly close.